Spots and freckles on human skin have been known to be caused by formation of melanin in skin tissues due to sunburn or the like. Also, formation of melanin through several steps from tyrosine by enzymic oxidation with a tyrosinase is known. Thus, suppression of spots and freckles in human skin can be attained by inhibition of tyrosinase activity. Tyrosinase inhibitory substances such as arbutin, kojic acid and casein hydrolysates are known and have been used as effective ingredients in compositions for human fair-skin up to date. Furthermore, novel substances which can inhibit tyrosinase activity and be used as an effective ingredient for human fair-skin are now under investigation.
In addition, various polysaccharide producing lactic acid bacteria are also known. Some lactococci such as Streptococcus lactis, Lactoncoccus lactis, Streptococcus cremoris and Lactococcus cremoris have been reported to produce phosphorylated polysaccharides (Japanese published unexamined patent application No. 229702 (1991); Nakajima et al., Carbohydr. Res., 224, pp. 245-253 (1992)). Furthermore, some lacobacilli such as Lactobacillus sake are also reported to produce phosphorylated polysaccharides (WO94/12656). All these phosphorylated polysaccharides have repetitive definite sequences of sugar chain of monosaccharides such as glucose, galactose and rhamnose bound directly or indirectly through the other monosaccharide with phosphoric acid residue in monosaccharide or glycerol residue as a side chain, and are different from neutral polysaccharides. Two of three oxy-acids in the phosphoric acid residue participate in the ester bindings with monosaccharides, and one remains free and can participate in the reaction with the other compounds.
The inventors of the present invention have been eagerly investigating for a compound which can be used as an effective ingredient for human fair-skin and found that the phosphorylated polysaccharides produced by lactic acid bacteria and known as antitumor substances inhibit the formation of melanin. The inventors further prepared compositions for fair-skin containing the phosphorylated polysaccharides. Thus, the object of the present invention is to provide compositions for fair-skin containing the novel effective components.